Flotation apparatus and process



no. GROSS, R. P. .AKI N SAND 1. w. BUCHER. FLOTATION APPARATUS AND PROCESS.

"APPLICATION FILED N0v.5, 1919. I 1,401,535. latented D60. 27, 1921 s SHEETSSHEET 1.

ATTORNEY.

F; D. (moss, R. P. AKINSAND J. w. BUCHER.

FLOTATION APP ARATUSAND PROCESS.

v I APPLiCATI ON FILED novfs, 191 1,401,535.

Patentd Dec. 27, 1921.

3 SHEETS-SHEET 3.

" INVENT RS M7 QI Z ATTORNEY rnnnmox DANIEL enoss,

f UNITED STATES PATENT OFFICE.

RANDALL AK INS, AN D JOHN WILLIAM ER,

'01 DENVER, COLORADO,

rnorarron' APPARATUS AND rnocnss.

To all whom it may concern:

Be it known that we, FREDERICK- D. GRoss,

RANDALL P. Annie, and JOHN W. Buonsn,'

citizens of the United States,residents-of Denver, Colorado, have invented certain .new

and, useful Improvements'in Flotation Apparatus and Processes,-of which the follow-- ing is a specification.

Our present inventionrelates to improvements in apparatus for the flotation of -sul.-

fids' or other mineral substances, so as toseparate them from the other constituents of the ores in which they occur.

'In the flotation process, the frothin'g of the mineral contents depends upon bringing of the'mineralparticles into intimate contact with air bubbles, so that these mineral particles attach themselves to thevminuteair bubbles and are thus carried to the surface to the bubbles and of the liquid and floated while the other constituents of they ore do not attach themselves are thusnotcarried to the surface." t

The bubblesof air rising to the surface of the liquid and carrying the mineral. particles with them, 'form What iscalled in metallurgical parlance, froth, andfthis froth is allowed'or caused to overflow a weir at the top of the tank'and is collected for further treatment. 'Theother constituents of the ore are withdrawn from the tankbelow i the frothing surface. 'Two embodiments of ourinvention are shownin the accompanysectional views and a longitudinal sectional I ing drawin in which:

Figure 1 1s a transverse sectional'view and Fig. 2 a longitudinal sectional :view of an apparatus comprising three frothing compartmentswith spitzkasten on the side for the overflow of the froth and the settling back of the other constituents of the ore. Figs. 3, 4 and 5 are respectively'transverse view of a modified form of apparatus comprising two frothing compartments, and two spitzkastenor settling compartments.

In these drawingsthe same' or similar reference characters indicate'identical or similar parts and areso referred to in the following a description. The machine consists essentially of 'a tank A- partiallyor completely in-' closed and divided by partitions A into a plurality of compartments which are in com munication at the bottom by ports ,Located in each compartment to one side of the center thereof is a vertically dmpoled,

Specification of Letters Patent.

sides of the machine as indicated at rotor, mounted on theihorizontal shaft N ournaled in suitably packed bearings Q and which may be driven by suitable means, as

"for instance the pulley 0. Each rotor is made up of spiral vanes B leading from the outer periphery toward the center, and sides B llnc'losing such vanes, therebyproviding Patented Dec. 27, 1921.

Application filed November 5, 1919. Serial in). 335,951.

tral shaft is a cylindrical'screen F, the vanes B and the passages Eterminating at this screen. On the top of the tankA above each rotor is an air chamber G connected to the 1 atmosphere by means of apipeD in which islocated a regulating val'veD. The screen F is extended into the space at the side of its rotor and surrounding that portion ofthe screen is another cylindricahscreen G to further assist in breaking up the air into .minute bubbles and causing froth.

The spitzkasten in Fig. 1 is shown at H and is provided with a solid ballle I for the purpose of directing the flow of the pulp and the return of the solids, and a perforatedbaflie J for the purpose of directing the flow and also of breaking up any 'wave motion so as to p esent a rather quiescent surface to'. the liquid.

The overflow weir'for the t'roth is shown at K which determinesthe 'froth level T. I

The, water level is shown at L and is regulated by the height ofthe discharge pipe S,

which being on. a swivel gives means for adjustin'g. For regulating the velocity of flow or the height of discharge of the frothed material from the frothin compartment to the spitzkasten we provi e a'slldable gate Pulp is fed into the machine at R and delivered to the underside of the'rotorand advanced from one compartment tothe other-through the openingsU. r

The, over-flowed 'froth '5 carried away from themachine'by means of'the launder In the machine shown in Figs. 3, land 5 we provide a tank divided into two compartments, and locate in each compartment two sets of baffles I and J the annular screen G being omitted inthis form. We

also rovide in this form launders for the Y over owed or decanted froth on gpwsite Inclined lanes P serve the pur use of v 60 through the rotor content toward the discharge end of the machine while in the center of theseincline'd planes P are return circulating ducts or passageways W leading back toward the vfront end of the machine, which passageways or. ducts narrow asthey go back toward the, front end of the machine, so'as to increase the velocity of the pulpv and- 1 keep thepassages clear. These return pas-- sages are for the purpose of keeping the f rotor in balance and maintaining a constant water level in all compartments of the ,machine. In'this form the heavier parts of the non-floatable material 'are:' discharged from the tank A through the pipe and valve shown atS', and the lighter portions of i the nonfloatable material may be carried up with the water through the passage X and- I overflow" the adjustable weir 'Y' into the zo launder Z and thence tol'th'e'pipe s Havingthus describedthe construction and arrangement of parts of the machine,

the operation'may bedescribed as follows: Finely pulverized ore and water with a small amount, of frothing agent are fed into i' the 'machineat, R, filling the machine or v tank .to the water level L. As the rotor v revolvesin the direction of the arrow shown 1 in the air chamber C, air istrapped in the channels E between the'vanes B and thesidesof the vanes B and as the vanes reach the] water level F L this air is forced with the 'water and ore toward; and through the centralscreen F.- Inpassing 85 through this center screen the air is broken intosmall bubbles which pass outward as shown by direction of arrows in Figs. 2 and 5,"and outward through screen G shown in Fig. 2. a

40 The desired: amount. of air for proper froth formation is admitted to the air chamber C by means of the controlling As the frothedmaterial passes into the ipitzkasten under the slidable i .1, or through the screen 4, it strikes the solid baflles I or I I gate M in and passing upward flows toward the weir K.?, The heavier unfrothed mineral and the non-frothable material circulate downward, and are carried back and into the rotor and again subjected to an aeration. I In the apparatus shown in Figs 3 to 5 the non-frothable material circulates through '55 thescreen F onto the inclined plane P and is soon advanced through the machine and out toward the discharge, while the lighter material is carried back through the passage W and given a second treatment Having thus described our 'we claim is v1 The herein described method of sepa- '-rat1 ng minerals by the flotation process which consists in successively isolating and invention what comminglingdefinite quantities of a froth producing mineral containing liquid and air .to thoroughly commingle and aerate the same, and thereafter directly releasin said definite quantities of aerated liquid below the surface of a body of similar liquid to effect frothing thereof.

2. In a flotation apparatus, a suitable tank having an open and closed compartment, means for admitting a regulable quantity of air to said closed compartment, a vertically disposed rotor journaled in said closed compartment'on a horizontal axis and having blades formed to. segregate and draw toward the axis both, air and liquid, said rotor having a direct discharge into the body of liquid in said open compartment below the surface of the liquid therein to produce froth, and' an overflow weir for said open compartmentfor the froth. ..3. Ina flotation'machine, a tank havin a' closed compartment and an open compartment, a rotor in said closed compartment rotating on a horizontal axis and adapted to be partially submerged, said ro-' torhaving spiral passages leading from its periphery toward the center, a perforate mixture of air and liquid is forced into said open compartment, and an overflow weir .for

said open compartment to remove froth, saidmember near the center through which the c overflow weir being above the level of said perforated member.

4, In a flotation apparatus, a tank havthe top, of said screen, and an overflow weir v for said open compartment. 7 5. In a flotation apparatus, a tank havin one compartment and having a passage leading from the periphery toward the center, acylindrical screen at the center of the rotor at which said passage terminates, said screen having a portion projecting into the other compartment, means or maintaining a liquid level in said tank above the top of said screen, baflies located in said other compartment above said projecting screen portion, and an overflow weir for said other compartment.

6. In a flotation apparatus, a tank hav ing a pair of adjoining compartments communicating at the bottom, a rotor mounted in one compartment and having a plurality inga pair ofadjoining compartments communicating at the bottom, a rotor mounted of spiral passages leading from the periphery toward the center, a cylindrical screen at the center of the rotor at which said passages terminate, said screen havlnga por-.

tion projectinginto the other. compartment, means for maintaining a liquid level in said tank above the top of said screen, baffles located in said other compartment above said projecting screen portion, a deflector located over said communication .between the compartments, and an overflow weir for said other compartment.

7. In aflotation apparatus, a containing tank having a closed compartment and an.

open compartment, a vertically-disposed 'rotor in said closed compartment having passages leading from the periphery toward the center, a cylindrical screen at the center tnres.

of said rotor at which said passages terminate, said screen having a portion exsaid open compartment above the level of said screen portion, a conduit leadingfro'm said open compartment to saidzclosed compartment, an overflow .weir on said open compartment to remove froth, means for maintaining a liquid level insaid compartments above the top of the screen, and means for'removing any desired proportion of the 'non-frothing material fro'm said open comtending into the open chamber, bafiies-in whereof, we afiix our signa- 

